Comment by bachmeier

I can say for sure that TiddlyWiki had backlinks many years before Roam existed.

Edit: Okay, I was curious, so I searched the Google Groups page, and found it mentioned as an existing feature in 2006: https://groups.google.com/g/tiddlywiki/c/KQRS-_sKukQ/m/DXZk9...

It is referenced as a feature on WikiMatrix, so it was clearly an established feature for wikis by that point.